The Cardiovascular System

Question 1

What are the 2 circulation loops?

Answer 1

Pulmonary circulation loop –> through the lungs to oxygenate. Systemic circulation loop –> through the body to oxygenate tissues and receive deoxygenated blood

Question 2

What is the volume of blood in the body?

Answer 2

5L

Question 3

What has the greatest surface area in the CVS?

Answer 3

Capillaries

Question 4

Where is the majority of the blood found?

Answer 4

65% blood in peripheral veins

Question 5

What is cardiovascular bridging?

Answer 5

compression (due to beating heart) of a segment of coronary artery during systole = narrowing that reverses during diastole

Question 6

In what manner does the heart contract?

Answer 6

Contracts in helical manner

Question 7

What are end arteries?

Answer 7

terminal artery that doesn’t have any secondary means of flow/no collateral circulation, if blocked very dangerous = central artery to retina

Question 8

What is collateral circulation?

Answer 8

circulation that develops to bypass occlusion (stenosis) to maintain blood supply

Question 9

Name the 4 values and the number of valve flaps

Answer 9

aortic (3), pulmonary (3), tricuspid (3), mitral (2)

Question 10

List the stages of cardiac conduction

Answer 10

SA node: pacemaker. AV node: momentary pause of conduction at AV so stop simultaneous contraction = AV DELAY. Bundle of his. L/R bundle branch. Purkinje fibres

Question 11

Where is the apex of the heart anatomically?

Answer 11

5th intercostal space

Question 12

Where do the coronary arties branch from?

Answer 12

Aorta

Question 13

What happens in systole?

Answer 13

Left ventricle contraction = BP in aorta to rise To 120mm Hg. Walls of elastic aorta (and other elastic arteries) stretch

Question 14

What happens in diastole?

Answer 14

Aortic semilunar valve closes. Walls of aorta recoil, maintaining pressure on the blood + moving it towards heart + smaller vessels. Pressure drops to 70-80mm Hg

Question 15

Define the term: capacitor vessel

Answer 15

elastic arteries act as pressure reservoir

Question 16

What are the layers of the vessels?

Answer 16

Layers = tunica intima –> tunica media (elastin fibres) –> tunica adventitia

Question 17

What is the main structural difference between arteries and veins?

Answer 17

Arteries = thick tunica media. Veins = valves

Question 18

What is the most common site for an aneurysm and why?

Answer 18

most common site = intrarenal region of aorta due to drop in elastic fibre level = weaker vessels

Question 19

How does vessel constriction take place?

Answer 19

neurotransmitter migrates through outer layer of vessel, reaches tunica media, layer with muscle fibres, cells are depolarised, depolarisation propagates to all cell via gap junctions = contraction

Question 20

What is the name for the band of smooth muscle that adjusts blood flow into capillaries?

Answer 20

Precapillary sphincter

Question 21

Where is blood velocity at its lowest and what benefit does this give?

Answer 21

Capillaries –> blood velocity is at its lowest = time for gas/nutrient exchange

Question 22

How does venous blood return from the periphery?

Answer 22

Calf muscle pumping: skeletal muscle contraction, propagates blood back to heart. At rest: breath in, diaphragm down, intrathoracic pressure goes down, blood rushes to atrium. Valves in veins of lower limbs – no veins in intraabdominal, intrathoracic or neck veins

Question 23

What is heart failure?

Answer 23

floppy L ventricle, blood pumped at reduced volume, due to hypertension, coronary arterial diseases, HA, cardiomyopathy = more blood volume in the LV but lower stoke volume

Question 24

What causes pulmonary oedema?

Answer 24

LVF, left ventricular failure –> = pulmonary oedema = pooling in the ventricle, goes back into lungs, pressure in the blood vessels increases as volume increases, pressure pushes fluid into alveoli

Question 25

What is starlings law of the heart?

Answer 25

Stroke volume of heart goes up in proportion to end diastolic volume = more you fill heart, better it contracts

Question 26

What vessel has the largest diameter?

Answer 26

Vein

Question 27

What vessels supply blood to the capillary bed?

Answer 27

Metarterioles

Question 28

What is the main structure at the anterior of the heart?

Answer 28

R atrium, R ventricle

Question 29

What is the main structure posterior on the heart?

Answer 29

L atrium, L ventricle

Question 30

List the order of blood flow around the cardio-respiratory system

Answer 30

Superior/Inferior vena cava, right atria, tricuspid valve, right ventricle, pulmonary valve, pulmonary arteries, lungs, right and left pulmonary veins, left atria, mitral valve, left ventricle, aortic valve, aorta, arteries, arterioles, metarterioles, capillaries, post capillary venules, venules, veins –> back to superior/inferior vena cava.

Question 31

What is a healthy BP?

Answer 31

120/80